May be a stupid question
#1
AFM Crusader
Thread Starter
iTrader: (19)
Join Date: Oct 2004
Location: Wayne, NJ
Posts: 4,679
Total Cats: 342
May be a stupid question
But why would you stroke an engine and maintain a low compression ratio? Don't you stroke an engine to increase the compression ratio? I'm not kidding, I really want to know why.
#3
Supporting Vendor
iTrader: (33)
Join Date: Jul 2006
Location: atlanta-ish
Posts: 12,659
Total Cats: 134
It's a way to increase displacement. You can only increase the circumference (over bore) of the cylinder to a point. Shave off too much, the block can loose strength, and possibly deform under load.
#4
AFM Crusader
Thread Starter
iTrader: (19)
Join Date: Oct 2004
Location: Wayne, NJ
Posts: 4,679
Total Cats: 342
OK, I went back to school.
http://en.wikipedia.org/wiki/Engine_displacement
So the compression ratio would be adjusted with the shape of the top of the piston in relation to the top of the cylinder to keep it low when stroking to increase displacement.
Seems to make sense. Guess an old dog can learn; sometimes
http://en.wikipedia.org/wiki/Engine_displacement
So the compression ratio would be adjusted with the shape of the top of the piston in relation to the top of the cylinder to keep it low when stroking to increase displacement.
Seems to make sense. Guess an old dog can learn; sometimes
#6
AFM Crusader
Thread Starter
iTrader: (19)
Join Date: Oct 2004
Location: Wayne, NJ
Posts: 4,679
Total Cats: 342
No, I was sitting with a friend the other day wondering why you would want to stroke a turbo engine. In the old days (like the Jurassic period) we would have an engine bored to increase displacement and stroked or the head shaved to increase compression.
It was foreign to me why you would want to increase compression on a turbo engine, not thinking about just doing it for displacement when you couldn't bore it any further or not wanting to add heavier(read larger diameter) pistons.
Remember, my days of engine technology come from big iron blocks.
It was foreign to me why you would want to increase compression on a turbo engine, not thinking about just doing it for displacement when you couldn't bore it any further or not wanting to add heavier(read larger diameter) pistons.
Remember, my days of engine technology come from big iron blocks.
#15
People run low compression because it makes tuning the car that much easier.
It's just easier to up the boost some... to make up for the loss of power with lower compression.
#16
Junior Member
iTrader: (1)
Join Date: Oct 2004
Location: Haarlem ,the Netherlands
Posts: 453
Total Cats: 0
stroking an engine does not mean the compression will be higher.
You can add more cc by enlarging the bore, but thats not stroking.
Stroking is to machine a custom crankshaft with custom shorter rods so that the cilinder goes deeper into the block. The cylinder will maintain the normal top level.(fm stroker kit)
You are increasing stroke, not bore.
I now some people that work there oem crankshaft so the new rod bearring will be smaller. You need to shave the crank towards the outside.
You try to get more stroke so youll need smaller rodbearrings and shorter rods.
3mm shave equals 6mm displacement. That makes a 1840cc miata an 1904 cc
(as you see english is not my main language)
You can add more cc by enlarging the bore, but thats not stroking.
Stroking is to machine a custom crankshaft with custom shorter rods so that the cilinder goes deeper into the block. The cylinder will maintain the normal top level.(fm stroker kit)
You are increasing stroke, not bore.
I now some people that work there oem crankshaft so the new rod bearring will be smaller. You need to shave the crank towards the outside.
You try to get more stroke so youll need smaller rodbearrings and shorter rods.
3mm shave equals 6mm displacement. That makes a 1840cc miata an 1904 cc
(as you see english is not my main language)
#17
Turbo's prefer as much compression as you can get. But the knock threshold and such becomes more dangerous with higher compression.
People run low compression because it makes tuning the car that much easier.
It's just easier to up the boost some... to make up for the loss of power with lower compression.
People run low compression because it makes tuning the car that much easier.
It's just easier to up the boost some... to make up for the loss of power with lower compression.
#18
stroking alone will increase compression(more swept volume into the the same size combustion chamber), as mentioned before there are measures you can take to tailor you compression as needed
stroking an engine does not mean the compression will be higher.
You can add more cc by enlarging the bore, but thats not stroking.
Stroking is to machine a custom crankshaft with custom shorter rods so that the cilinder goes deeper into the block. The cylinder will maintain the normal top level.(fm stroker kit)
You are increasing stroke, not bore.
I now some people that work there oem crankshaft so the new rod bearring will be smaller. You need to shave the crank towards the outside.
You try to get more stroke so youll need smaller rodbearrings and shorter rods.
3mm shave equals 6mm displacement. That makes a 1840cc miata an 1904 cc
(as you see english is not my main language)
You can add more cc by enlarging the bore, but thats not stroking.
Stroking is to machine a custom crankshaft with custom shorter rods so that the cilinder goes deeper into the block. The cylinder will maintain the normal top level.(fm stroker kit)
You are increasing stroke, not bore.
I now some people that work there oem crankshaft so the new rod bearring will be smaller. You need to shave the crank towards the outside.
You try to get more stroke so youll need smaller rodbearrings and shorter rods.
3mm shave equals 6mm displacement. That makes a 1840cc miata an 1904 cc
(as you see english is not my main language)
#19
Junior Member
iTrader: (1)
Join Date: Oct 2004
Location: Haarlem ,the Netherlands
Posts: 453
Total Cats: 0
Stroking an engine is not something you can easely do.
True, if you compres more air youll have more compression...
Of course you can do anything to keep the compression lower (domed
pistons) Moving the lower pistonrings under the (where the rod meets the piston) dowel pins???????? (dont know the name)
Exotic stuf....
Now find someone who makes a custem stroker for cheap that can handle up to 30psi (3 bar map sensor)
True, if you compres more air youll have more compression...
Of course you can do anything to keep the compression lower (domed
pistons) Moving the lower pistonrings under the (where the rod meets the piston) dowel pins???????? (dont know the name)
Exotic stuf....
Now find someone who makes a custem stroker for cheap that can handle up to 30psi (3 bar map sensor)
Thread
Thread Starter
Forum
Replies
Last Post
bigmackloud
Miata parts for sale/trade
19
01-08-2021 11:24 AM
JesseTheNoob
DIY Turbo Discussion
15
09-30-2015 02:44 PM